function IsPC() {
  var userAgentInfo = navigator.userAgent
  var reg = new RegExp('(Android|iPhone|SymbianOS|Windows Phone|iPad|iPod)', 'ig')
  var isPC = !reg.test(userAgentInfo)
  return isPC
}
var initFontSize = function () {
  var n = document.getElementsByTagName('html')[0],
    e = document.documentElement.clientWidth
  if (IsPC()) {
    if (e > 750) {
      n.style.fontSize = '16px'
    } else {
      n.style.fontSize = (e / 750) * 20 + 'px'
    }
  } else {
    n.style.fontSize = (e / 750) * 20 + 'px'
  }
}
initFontSize()
window.οnresize = function () {
  initFontSize()
}
// 1：10
/* <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0"></meta> */
